Not Applicable
Not Applicable
Field of the Invention
The present invention relates to a wellbore system comprising a borehole formed in the earth formation, the borehole being provided with a valve having a passage for a stream of fluid flowing from an upstream side of the valve to a downstream side of the valve. In the practice of production of hydrocarbon fluid from a wellbore valves are generally applied to control the flow rate of the produced fluid or to shut off the wellbore in case of an emergency. Such valves generally allow flow of fluid through the borehole in both directions thereof.
It is an object of the invention to provide a wellbore system comprising a borehole formed in the earth formation, the borehole being provided with a valve allowing flow of fluid in one direction through the borehole and preventing flow of fluid in the other direction through the borehole.
In accordance with the invention there is provided a wellbore system comprising a borehole formed in the earth formation, the borehole being provided with a valve having a passage for a stream of fluid flowing from an upstream side of the valve to a downstream side of the valve, a closure member exposed to a drag force exerted by the stream and movable relative to the passage between an open position in which the closure member allows fluid to flow through the passage and a closed position in which the closure member closes the passage, said drag force biasing the closure member to the open position thereof, and a spring exerting a spring force to the closure member biasing the closure member to the closed position, wherein the spring force when the closure member is in the closed position exceeds a selected lower limit of the drag force.
Suitably the valve is oriented in the borehole in a manner that the closure member is biased to the open position thereof by the drag force exerted by the stream pumped through the borehole in downward direction thereof.
Preferably the valve is oriented in the borehole in a manner that the closure member is biased to the open position thereof by the drag force exerted by the stream flowing through the borehole in upward direction thereof.